Substrate holding apparatus

ABSTRACT

A substrate holding apparatus can accurately control temperature of a substrate in a direct manner with a relatively simple arrangement. The substrate holding apparatus has a top ring configured to hold a substrate to be polished and press the substrate against a polishing surface and an air bag attached to the top ring so as to be brought into contact with a rear face of the substrate. The substrate holding apparatus also has a regulator operable to regulate a temperature control fluid to be supplied into the air bag and a flow regulating valve operable to regulate a flow rate of the temperature control fluid discharged from the air bag.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a substrate holding apparatus, and moreparticularly to a substrate holding apparatus in a chemical mechanicalpolishing for polishing a substrate such as a semiconductor wafer to aflat mirror finish.

2. Description of the Related Art

As semiconductor devices have become more highly integrated in recentyears, circuit interconnections have become finer and distances betweenthose circuit interconnections have become smaller. In the case ofphotolithography, which can form interconnections that are at most 0.5μm wide, it is required that surfaces on which pattern images are to befocused by a stepper should be as flat as possible because the depth offocus of an optical system is relatively small. In order to planarizesuch a semiconductor wafer, there has been used a polishing apparatusfor performing chemical mechanical polishing (CMP).

This type of chemical mechanical polishing apparatus comprises apolishing table having a polishing pad (polishing cloth) attached to anupper surface of the polishing table, and a top ring for holding asubstrate to be polished, such as a semiconductor wafer. The polishingtable and the top ring are rotated at independent rotational speeds,respectively. The top ring presses the substrate against the polishingpad under a predetermined pressure. A polishing liquid (slurry) issupplied from a polishing liquid supply nozzle onto the polishing pad.Thus, a surface of the substrate is polished to a flat mirror finish.

FIG. 1 is a schematic view showing a main portion of a conventionalpolishing apparatus. The conventional polishing apparatus includes arotatable polishing table (turntable) 102 having a polishing pad(polishing cloth) 100 attached to an upper surface of the polishingtable 102, a top ring 104 for holding a semiconductor wafer (substrate)W, and a polishing liquid supply nozzle 106 for supplying a polishingliquid Q to the polishing pad 100. The top ring 104 is configured torotate the semiconductor wafer W and press the semiconductor wafer Wagainst the polishing pad 100. The top ring 104 is connected to a topring shaft 108, which is vertically movable via an air cylinder providedin a top ring head (not shown).

The top ring 104 has an elastic pad 110 attached to a lower surface ofthe top ring 104. For example, the elastic pad is made of polyurethane.The semiconductor wafer W is held by the top ring 104 in a state suchthat the semiconductor wafer W is brought into contact with the elasticpad 110. Further, the top ring 104 has a cylindrical guide ring 112provided at a peripheral portion of the top ring 104. The guide ring 112serves to prevent the semiconductor wafer W from being separated fromthe lower surface of the top ring 104 during polishing. The guide ring112 is fixed to the peripheral portion of the top ring 104. The guidering 112 has a lower end located at a position lower than a holdingsurface of the top ring 104 and accordingly forms a recessed portion atan inward position of the guide ring 112. Thus, a semiconductor wafer Wto be polished is held within the recessed portion of the top ring 104so as not to be ejected from the top ring 104 during polishing.

With the conventional polishing apparatus, the semiconductor wafer W isheld on the lower surface of the elastic pad 110 in the top ring 104 andpressed against the polishing pad 100 on the polishing table 102 by thetop ring 104. The polishing table 102 and the top ring 104 are rotatedso as to move the polishing pad 100 and the semiconductor wafer W fromthe polishing liquid supply nozzle 106. For example, a suspension offine abrasive particles in an alkali solution is used as the polishingliquid. Thus, the semiconductor wafer W is polished to a flat mirrorfinish by a combined effect of a chemical polishing effect attained bythe alkali and a mechanical polishing effect attained by the abrasiveparticles.

In the aforementioned polishing apparatus, various complicated factorswhich may affect the amount of polishing should be controlled in orderto planarize a semiconductor wafer W over the entire surface thereofwith high accuracy. Such factors include a relative sliding speedbetween the semiconductor wafer W and the polishing table 102, theamount (or distribution) of polishing liquid at an interface (polishinginterface) between the semiconductor wafer W and the polishing pad 100,a pressing force applied to the semiconductor wafer W to press thesemiconductor wafer W against the polishing pad 100 by the top ring 104,the temperature of the polishing interface, and the like.

When an acid or alkali polishing liquid is used to perform a chemicalmechanical polishing process (CMP), the temperature of the polishinginterface exerts a great influence on a polishing rate. Additionally, ifthe top ring 104 is increased in temperature, the top ring 104 isdeformed so as to exert an adverse influence on a pressing force. Thus,the control of the temperature of the polishing interface has twoaspects with respect to a level of planarization.

An example of a substrate holding apparatus including a means forcontrolling a temperature of a polishing interface is disclosed inJapanese laid-open patent publication No. 2000-225559, the relevantparts of which are hereby incorporated by reference. Specifically, thesubstrate holding apparatus includes a holding plate having a substrateholding surface and an elastic pad attached to the holding surface ofthe holding plate. A substrate is held via the elastic pad on thesubstrate holding surface, and a surface of the substrate to be polishedis pressed against a polishing surface on a polishing table. Grooves areformed in the substrate holding surface of the holding plate. Thegrooves are supplied with a fluid controlled in temperature. Thus, thetemperature of the substrate is controlled via the elastic pad.

FIG. 2 is a cross-sectional view showing a substrate holding apparatushaving fluid communication grooves 128 for temperature control asdisclosed in Japanese laid-open patent publication No. 2000-225559. InFIG. 2, components are illustrated in a simplified manner for easyunderstanding. As shown in FIG. 2, the substrate holding apparatus has atop ring 104 for holding a wafer W to be polished, an elastic pad 110attached to a lower surface of the top ring 104, and pressure controlunits (regulators) 125 for controlling a pressure of a temperaturecontrol fluid 129. A plurality of communication grooves 128 are formedin the top ring 104. The temperature control fluid 129 is suppliedthrough the pressure control unit 125 into the communication grooves 128so as to cool a lower surface of the top ring 104. Because the coolingeffect is transmitted to the wafer W via the elastic pad 110 by heatconduction, the cooling effect is adversely reduced by the elastic pad110.

Further, no flow regulating valve is provided downstream of thecommunication grooves 128, but the regulator 125 is provided downstreamof the communication grooves 128. Accordingly, the temperature controlfluid 129 is supplied to the communication grooves 128 only when thepressure of a fluid in the communication grooves 128 is lowered. Thus,the cooling effect is unsatisfactory in the conventional substrateholding apparatus. Furthermore, because the temperature control fluid129 may leak from a periphery of the elastic pad 110 into the wafer W tocause uneven temperature control and contamination of the wafer W, aliquid cannot be used as the temperature control fluid 129.

Additionally, it is necessary to form a plurality of communicationgrooves 128 in the top ring 104 and further form a plurality of passagesfor allowing the temperature control fluid 129 to flow through thecommunication grooves 128. Thus, many troublesome processes are requiredto form grooves and holes, and the structure of the top ring 104 becomescomplicated. Accordingly, the use of the communication grooves 128 iseffective rather in applying a back pressure to a rear face of the waferW.

In order to solve the above drawbacks, there has been proposed asubstrate holding apparatus having an air bag as shown in FIG. 3. Thesubstrate holding apparatus has a top ring 104 for holding a wafer W ona lower surface thereof, a top ring shaft 108 for rotating the top ring104, and an air bag 124 provided in the top ring 104 in a manner suchthat the wafer W is brought into contact with the air bag 124. The airbag 124 is supplied with a fluid 129 controlled in temperature through aregulator 125. While the substrate holding apparatus shown in FIG. 2controls the temperature of the wafer W via the elastic pad 110, thesubstrate holding apparatus shown in FIG. 3 controls the temperature ofthe rear face of the wafer W directly by the temperature control fluid129 in the air bag 124. The air bag 124 in this substrate holdingapparatus is mainly used to uniformly press the wafer W Specifically,the regulators 125 are employed in order to adjust the pressure of theair bag 124 at a predetermined value. Accordingly, a fluid 129 flowsinto the air bag 124 only when an internal pressure of the air bag 124is lower than the predetermined value.

Although the substrate holding apparatus shown in FIG. 3 is configuredto directly control the temperature of the wafer, no attention is paidto discharge of the temperature control fluid 129 from the air bag 124.Accordingly, the temperature control fluid 129 above the rear face ofthe wafer W is not replaced and thus serves merely as a fluid forapplying a back pressure to control a pressing force of the wafer W. Asa result, the wafer W is increased in temperature according to thepolishing process. In a case of a copper CMP (chemical mechanicalpolishing), if the temperature of a wafer becomes greater than a certainvalue, a polishing rate is lowered, particularly, at a central portionof the wafer.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above drawbacks. Itis, therefore, an object of the present invention to provide a substrateholding apparatus which can accurately control temperature of asubstrate in a direct manner with a relatively simple arrangement.

According to a first aspect of the present invention, there is provideda substrate holding apparatus which can accurately control temperatureof a substrate in a direct manner with a relatively simple arrangement.The substrate holding apparatus has a top ring configured to hold asubstrate to be polished and press the substrate against a polishingsurface, and an air bag attached to the top ring so as to be broughtinto contact with a rear face of the substrate. The substrate holdingapparatus also has a regulator operable to regulate a temperaturecontrol fluid to be supplied into the air bag, and a flow regulatingvalve operable to regulate a flow rate of the temperature control fluiddischarged from the air bag.

According to a second aspect of the present invention, there is provideda substrate holding apparatus which can accurately control temperatureof a substrate in a direct manner with a relatively simple arrangement.The substrate holding apparatus has a top ring configured to hold asubstrate to be polished and press the substrate against a polishingsurface, and an air bag attached to the top ring so as to be broughtinto contact with a rear face of the substrate. The air bag includes aplurality of chambers. The substrate holding apparatus also has aplurality of regulators operable to regulate temperature control fluidsto be supplied into the corresponding chambers in the air bag, and aplurality of flow regulating valves operable to regulate flow rates ofthe temperature control fluids discharged from the correspondingchambers in the air bag. In this case, the substrate can be controlledin temperature at each local area of the substrate.

According to the present invention, a fluid (gas or liquid) controlledin temperature is supplied to the air bag near a rear face of thesubstrate (wafer) and discharged from the air bag. Thus, heat exchangecan efficiently be performed to stabilize the temperature of thesubstrate for a long term of a chemical mechanical polishing (CMP)process.

The substrate holding apparatus may include a thermometer provided inthe top ring or the air bag to measure a temperature of the substrateheld by the top ring. The thermometer may monitor the temperature of thesubstrate held by the top ring. The substrate can be controlled intemperature based on results monitored by the thermometer. The air bagmay comprise a close-type air bag or an open-type air bag.

According to a third aspect of the present invention, there is provideda substrate holding apparatus which can accurately control temperatureof a substrate in a direct manner with a relatively simple arrangement.The substrate holding apparatus has a top ring configured to hold asubstrate to be polished and press the substrate against a polishingsurface, and an air bag attached to the top ring so as to be broughtinto contact with a rear face of the substrate. The substrate holdingapparatus also has a regulator operable to regulate a temperaturecontrol fluid to be supplied into the air bag, and a thermometerprovided in the top ring or the air bag to measure a temperature of thesubstrate held by the top ring.

According to a fourth aspect of the present invention, there is provideda substrate holding apparatus which can accurately control temperatureof a substrate in a direct manner with a relatively simple arrangement.The substrate holding apparatus has a top ring configured to hold asubstrate to be polished and press the substrate against a polishingsurface, and an air bag attached to the top ring so as to be broughtinto contact with a rear face of the substrate. The air bag includes aplurality of chambers. The substrate holding apparatus also has aplurality of regulators operable to regulate temperature control fluidsto be supplied into the corresponding chambers in the air bag, and athermometer provided in the top ring or the air bag to measure atemperature of the substrate held by the top ring. In this case, thesubstrate can be controlled in temperature at each local area of thesubstrate.

The thermometer may monitor the temperature of the substrate held by thetop ring. The substrate can be controlled in temperature based onresults monitored by the thermometer. The air bag may comprise aclose-type air bag or an open-type air bag.

The above and other objects, features, and advantages of the presentinvention will be apparent from the following description when taken inconjunction with the accompanying drawings which illustrate preferredembodiments of the present invention by way of example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a conventional polishingapparatus;

FIG. 2 is a cross-sectional view showing a conventional substrateholding apparatus having a cooling mechanism for cooling a wafer;

FIG. 3 is a cross-sectional view showing a conventional substrateholding apparatus having an air bag;

FIG. 4 is a cross-sectional view showing a substrate holding apparatushaving a temperature control mechanism according to a first embodimentof the present invention;

FIG. 5 is a graph showing comparison of pad surface temperatures betweena case where a rear face of a wafer was cooled and a case a rear face ofa wafer was not cooled;

FIG. 6 is a cross-sectional view showing a substrate holding apparatushaving a close-type air bag according to a second embodiment of thepresent invention;

FIG. 7 is a cross-sectional view showing a substrate holding apparatushaving an open-type air bag according to a third embodiment of thepresent invention;

FIG. 8A is a cross-sectional view showing a substrate holding apparatushaving divided chambers in an air bag according to a fourth embodimentof the present invention;

FIG. 8B is a plan view showing the divided chambers shown in FIG. 8A;

FIG. 9 is a cross-sectional view showing a substrate holding apparatushaving a thermometer and an air bag into which a fluid controlled intemperature is introduced according to a fifth embodiment of the presentinvention; and

FIG. 10 is a cross-sectional view showing a substrate holding apparatushaving a thermometer and an air bag through which a fluid controlled intemperature flows according to a sixth embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A substrate holding apparatus according to embodiments of the presentinvention will be described below with reference to FIGS. 4 through 10.The present invention is not limited to the following embodiments. Likeor corresponding parts are denoted by like or corresponding referencenumerals throughout drawings, and will not be described belowrepetitively.

FIG. 4 is a schematic view showing a substrate holding apparatus 1according to a first embodiment of the present invention. The substrateholding apparatus 1 has a top ring 2 for holding a wafer W and pressingthe wafer W against a polishing surface on a polishing table, a shaft 3for rotating the top ring 2, an air bag 4 supplied with a temperaturecontrol fluid (fluid controlled in temperature) 9, a regulator 5 forregulating the temperature control fluid 9, and a flow regulating valve(speed controller) 6 for regulating a flow rate of the temperaturecontrol fluid 9 discharged from the air bag 4. The temperature controlfluid, the regulator 5, and the flow regulating valve 6 are configuredto control the temperature of a space between the top ring 2 and a rearface of the wafer W. The temperature control fluid 9 above the rear faceof the wafer W is replaced by a combination of the regulator 5, the flowregulating valve 6, and the air bag 4. A cooling device (not shown) isprovided for cooling the fluid 9 to be supplied into the air bag 4 at apredetermined temperature. The temperature control fluid 9 may comprisea gas such as dry air, nitrogen gas, or helium gas, or a liquid such aswater.

The air bag 4 presses the wafer W against a polishing table under auniform pressure. The regulator 5 maintains and regulates a pressure ofthe air bag 4. The temperature control fluid 9 flows through theregulator 5 into the air bag 4. The temperature control fluid 9 in theair bag 4 is continuously or intermittently discharged by the flowregulating valve 6. Heat exchange is performed between the wafer W andthe temperature control fluid 9. Thus, by adjusting the temperature ofthe temperature control fluid 9, the wafer W can be maintained at apredetermined temperature.

In the present embodiment, there is no elastic pad, which has a poorheat conductivity. Heat conduction is performed via a thin film of theair bag 4. As a result, even if a CMP process is performed to polish athick copper film for a long term, temperature increase is not caused.Accordingly, a high polishing rate can be maintained until completion ofthe polishing process. Further, even when a polishing process isperformed at a high pressing force and a high rotational speed in orderto increase a polishing rate, temperature increase can be prevented.

FIG. 5 is a graph showing temperatures of a polishing pad (polishingtable) at a portion immediately after a wafer had passed above theportion. FIG. 5 shows measurement results in case of the substrateholding apparatus 1 shown in FIG. 4 and the conventional substrateholding apparatus shown in FIG. 3. In the case of the substrate holdingapparatus 1 shown in FIG. 4, a rear face of a wafer was cooled by theaforementioned structure. In the case of the conventional substrateholding apparatus shown in FIG. 3, a rear face of a wafer was not cooledbecause a fluid was not replaced in an air bag. It can be seen from FIG.5 that temperature increase could be prevented when the rear face of thewafer was cooled. In the case where the rear face of the wafer was notcooled, temperature increase inhibited the reaction to thereby causetemperature decrease.

FIG. 6 is a schematic view showing a substrate holding apparatus 11employing a close-type air bag 14 according to a second embodiment ofthe present invention. FIG. 6 shows the substrate holding apparatus 11before a wafer W is held on a holding surface of the top ring 2. When achemical mechanical polishing process is performed, the top ring 2lowers a presser ring (not shown) downward by an air cylinder to pressthe presser ring against a polishing table (not shown) having apolishing pad attached thereon. Thus, the rear face of the wafer W isbrought into close contact with the lower surface of the air bag 14.Details of such mechanisms are disclosed in Japanese laid-open patentpublication No. 2000-225559.

As shown in FIG. 6, the close-type air bag 14 is of a balloon. Since apressurized temperature control fluid 9 is hermetically sealed in theclose-type air bag 14, the substrate holding apparatus 11 has a goodsealing performance. Since the pressurized temperature control fluid 9is brought into contact with the rear face of the wafer W via the airbag 14, the substrate holding apparatus 11 has a heat conductivity lowerthan that of a substrate holding apparatus employing an open-type airbag, which is described below.

FIG. 7 is a schematic view showing a substrate holding apparatus 21employing an open-type air bag 24 according to a third embodiment of thepresent invention. FIG. 7 shows the substrate holding apparatus 21before a wafer W is held on a holding surface of the top ring 2 as inthe case of FIG. 6. When the wafer W is polished, a lower surface of theair bag 24 is brought into close contact with the rear face of the waferW, as in the case of FIG. 6.

As shown in FIG. 7, the air bag 24 is open at a lower portion thereof.When the wafer W is polished, the air bag 24 is brought into contactwith the wafer W at a peripheral portion of the air bag 24 to form aseal portion. Thus, a pressurized temperature control fluid ishermitically sealed in the sealed portion in the air bag 24. The sealingperformance of the air bag 24 is less than that of a close-type air bagas shown in FIG. 6. However, since the pressurized temperature controlfluid 9 is brought into direct contact with the rear face of the waferW, it is possible to achieve efficient heat exchange.

FIG. 8A is a cross-sectional view showing a substrate holding apparatus31 employing a plurality of sets of regulators 5 and flow regulatingvalves 6 according to a fourth embodiment of the present invention. FIG.8A shows the substrate holding apparatus 31 immediately before a wafer Wis held on a holding surface of the top ring 2. FIG. 8B is a plan viewof an air bag in the substrate holding apparatus 31. The substrateholding apparatus 31 has an air bag 34 including a plurality of chambers34 a, 34 b, and 34 c divided in a radial direction. Temperature controlfluids 9 are separately supplied into the divided chambers 34 a, 34 b,and 34 c to thereby control a central portion, an intermediate portion,and a peripheral portion of the wafer W independently of each other.

The regulators 5 and the flow regulating valves 6 are provided so as tocorrespond to the divided chambers 34 a, 34 b, and 34 c. Temperaturecontrol fluids 9 are supplied at different flow rates into the dividedchambers 34 a, 34 b, and 34 c, respectively. Thus, the central portion,the intermediate portion, and the peripheral of the wafer W can becooled separately from each other.

With the air bags having the divided chambers 34 a, 34 b, and 34 c tocontrol the temperature of the wafer W, temperature control can beperformed at the respective areas of the wafer W. In a case of a copperCMP process, a polishing rate is lowered when the temperature of thewafer becomes larger than a certain value. Particularly, decrease of apolishing rate becomes significant at a central portion of a wafer whenthe temperature of the wafer is increased. According to the substrateholding apparatus 31 described above, the wafer W can intensively becooled at the central portion thereof Thus, it is possible toeffectively prevent decrease of a polishing rate.

In the above embodiments, a fluid 9 controlled in temperature isintroduced into the air bag to control the temperature of the wafer W.However, in order to perform accurate temperature control, it isnecessary to measure the temperature of the wafer W to be polished. In aconventional polishing apparatus, because the surface of the wafercannot directly be measured, the temperature of a polishing pad ismeasured at a position through which the wafer has passed to therebymeasure the temperature of the wafer. On the contrary, in the substrateholding apparatus employing an air bag without any elastic pads, thetemperature of the rear face of the wafer W can directly be measured.Accordingly, a thermometer may be provided in the top ring 2 to measurethe temperature of the rear face of the wafer W in the aboveembodiments. When the temperature of the wafer W is monitored by thethermometer, the temperature control of the wafer W can be performedmore accurately.

If a thermometer provided in the top ring is brought into direct contactwith the wafer, distortion is applied to the wafer W. Accordingly, anon-contact radiation thermometer is suitable for the thermometer tomeasure the temperature of the wafer W. It is desirable to use aninfrared thermometer as a radiation thermometer. In the case of aninfrared thermometer, an infrared ray permeates a Si wafer and is thussuitable only for a metal wafer. In the case of a radiation thermometer,when the air bag is made of a material which is permeated byelectromagnetic radiation (including light ray), the temperature of thewafer W can sufficiently be measured even if a measurement end of thethermometer is located above the air bag. However, even a thin film ofthe air bag inhibits permeation of electromagnetic radiation to someextent. Accordingly, when an open-type air bag as shown in FIG. 7 isused, the accuracy of the measurement can be improved because there isno films on a rear face of the wafer W.

FIG. 9 is a schematic view showing a substrate holding apparatus 41having a thermometer 10 in a top ring 2 according to a fifth embodimentof the present invention. When a thermometer 10 is provided in thesubstrate holding apparatus 41, it is not necessary to employ an air baginto which a fluid controlled in temperature is supplied through aregulator and a flow regulating valve as shown in FIG. 4. Specifically,as shown in FIG. 9, a fluid 9 controlled in temperature may simply beintroduced into an air bag 44. In FIG. 9, the thermometer 10 is providedin the top ring 2 or in the air bag 44.

FIG. 10 is a schematic view showing a substrate holding apparatus 51having a thermometer 10 in a top ring 2 or an air bag 4 according to asixth embodiment of the present invention. The substrate holdingapparatus 51 employs an air bag 4 into which a fluid 9 controlled intemperature is supplied through a regulator 5 and a flow regulatingvalve 6 as with FIG. 4. In FIG. 10, the thermometer 10 is provided inthe top ring 2 or in the air bag 4. Since the air bag 4 is supplied witha fluid 9 controlled in temperature, it is possible to control thetemperature of the wafer W more readily and more accurately.

As described above, according to a substrate holding apparatus for achemical mechanical polishing (CMP) apparatus, a fluid controlled intemperature is brought into contact with a rear face of a substrate tobe polished in order to stabilize variation of the temperature of thesubstrate during a CMP process. Accordingly, even if a CMP process isperformed for a long term, temperature increase is not caused. Further,even when a polishing process is performed at a high pressing force anda high rotational speed in order to increase a polishing rate,temperature increase can be prevented. Accordingly, a high polishingrate can be maintained until completion of the polishing process. Thus,the present invention is useful for a substrate holding apparatus in apolishing apparatus for polishing highly integrated semiconductor wafersto a flat mirror finish.

Although certain preferred embodiments of the present invention havebeen shown and described in detail, it should be understood that variouschanges and modifications may be made wherein without departing from thescope of the appended claims.

1. A substrate holding apparatus comprising: a top ring configured tohold a substrate to be polished and press the substrate against apolishing surface; an air bag attached to said top ring so as to bebrought into contact with a rear face of the substrate; a regulatoroperable to regulate a temperature control fluid to be supplied intosaid air bag; and a flow regulating valve operable to regulate a flowrate of the temperature control fluid discharged from said air bag. 2.The substrate holding apparatus as recited in claim 1, furthercomprising a thermometer provided in said top ring or said air bag tomeasure a temperature of the substrate held by said top ring.
 3. Thesubstrate holding apparatus as recited in claim 2, wherein saidthermometer monitors the temperature of the substrate held by said topring, wherein the substrate is controlled in temperature based onresults monitored by said thermometer.
 4. The substrate holdingapparatus as recited in claim 1, wherein said air bag comprises aclose-type air bag or an open-type air bag.
 5. A substrate holdingapparatus comprising: a top ring configured to hold a substrate to bepolished and press the substrate against a polishing surface; an air bagattached to said top ring so as to be brought into contact with a rearface of the substrate, said air bag including a plurality of chambers; aplurality of regulators operable to regulate temperature control fluidsto be supplied into the corresponding chambers in said air bag; and aplurality of flow regulating valves operable to regulate flow rates ofthe temperature control fluids discharged from the correspondingchambers in said air bag.
 6. The substrate holding apparatus as recitedin claim 5, further comprising a thermometer provided in said top ringor said air bag to measure a temperature of the substrate held by saidtop ring.
 7. The substrate holding apparatus as recited in claim 6,wherein said thermometer monitors the temperature of the substrate heldby said top ring, wherein the substrate is controlled in temperaturebased on results monitored by said thermometer.
 8. The substrate holdingapparatus as recited in claim 5, wherein said air bag comprises aclose-type air bag or an open-type air bag.
 9. A substrate holdingapparatus comprising: a top ring configured to hold a substrate to bepolished and press the substrate against a polishing surface; an air bagattached to said top ring so as to be brought into contact with a rearface of the substrate; a regulator operable to regulate a temperaturecontrol fluid to be supplied into said air bag; and a thermometerprovided in said top ring or said air bag to measure a temperature ofthe substrate held by said top ring.
 10. The substrate holding apparatusas recited in claim 9, wherein said thermometer monitors the temperatureof the substrate held by said top ring, wherein the substrate iscontrolled in temperature based on results monitored by saidthermometer.
 11. The substrate holding apparatus as recited in claim 9,wherein said air bag comprises a close-type air bag or an open-type airbag.
 12. A substrate holding apparatus comprising: a top ring configuredto hold a substrate to be polished and press the substrate against apolishing surface; an air bag attached to said top ring so as to bebrought into contact with a rear face of the substrate, said air bagincluding a plurality of chambers; a plurality of regulators operable toregulate temperature control fluids to be supplied into thecorresponding chambers in said air bag; and a thermometer provided insaid top ring or said air bag to measure a temperature of the substrateheld by said top ring.
 13. The substrate holding apparatus as recited inclaim 12, wherein said thermometer monitors the temperature of thesubstrate held by said top ring, wherein the substrate is controlled intemperature based on results monitored by said thermometer.
 14. Thesubstrate holding apparatus as recited in claim 12, wherein said air bagcomprises a close-type air bag or an open-type air bag.